


Immortal Exorcist

by YamiBaki



Series: Sons of Satan [2]
Category: Ao no Exorcist | Blue Exorcist
Genre: Blood, Death, Implied/Referenced Rape/Non-con, Loss of Virginity, M/M, Mephisto being a little shit, Mephisto x male reader, Murder, Reader is male, Suicide, Yaoi, ao no exorcist - Freeform, but will be funny, enjoy, exorcist reader, lots of shit will happen, male reader - Freeform, male reader x mephisto pheles, mephisto being annoying, not sure where this is going, reader has a temper, reader is strong
Language: English
Status: In-Progress
Published: 2016-09-11
Updated: 2016-09-11
Packaged: 2018-08-14 09:23:08
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 2
Words: 4,963
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8007850
Author URL: https://archiveofourown.org/users/YamiBaki/pseuds/YamiBaki
Summary: <blockquote class="userstuff">
              <p>Mephisto Pheles x Male Reader<br/>100 Theme Challenge</p><p>The boy was intriguing, he was also stubborn, short tempered and his pride was something that needed some work. But the headmaster found him amusing, and he did enjoy the thrill of the chase. But when a new power enters the picture, and the boy runs into the middle of it all, facing death head on, how will Mephisto handle it?</p>
            </blockquote>





	1. Introduction

**Summary for the Chapter:**

> Boy falls from bridge into oncoming traffic and Mephisto finds him interesting.

“Someone call an ambulance!” 

 

A woman screamed, as cars stopped and pedestrians ran up to the accident that had just occurred. Mephisto had also gotten out of his car, which had been a few feet away, to see if the one who jumped was still alive. He'd been out on a drive in his new care, while going under a bridge near the road a body dropped down in front of the car before his. A woman, who had been driving in the car up ahead, had gotten out of the driver's end and let out a scream. It must have been a bloody see, and that excited him. Of course, he needed to get out and 'make sure' it wasn't the body of a True Cross student. 

 

He's heard that the student suicide count will rise due to the stress of exams coming up, and that's the last thing he wanted. 

 

Making his way through, he stared with an indifferent expression at the body of a young boy laying on ground, blood surrounding him, soaking his clothes from head to toe. He looked around 15 to 16, Mephisto wasn't sure, especially since his baby face was covered in blood. 

 

“Oh God, I didn't run him over, I did not run him over I swear!” One man driving cried, going into a panic as the others voiced their concerns. And for some strange reason, Mephisto couldn't take his eyes off of the boy. Why was he there? Why did he jump? Unless he was pushed, but that wouldn't make sense since the boy laid on his back, eyes closed and arms spread out welcoming death. Taking a few steps closer, ignoring the woman asking him what he was doing, Mephisto knelt down and began to examine him. The boy wasn't bad looking, young with ageless skin, long lashes and-

 

“This boy is breathing...” He muttered, causing others to stand in silence, before moving closer with curiosity. He watched as the boy's chest began to rise and fall, which was odd since Mephisto could have sworn the boy wasn't breathing before. How was this possible? Glancing at the bridge above him, he knew that there was a good distance between the two, and with the way the boy's head met the cement ground, he wouldn't have, _shouldn't have_ , survived. 

 

“The ambulance is going to arrive shortly!” One of the pedestrians yelled, while Mephisto examined the body. He hummed to himself, reaching a gloved hand over to touch the boy's cold cheek. At that moment the boy opened his eyes and stared at the sky, taking in a deep breath before coughing hysterically. Many began to scream and back away, while Mephisto stood in his spot, eyes wide in confusion as he watched the boy cough out blood and breathing heavily. 

 

“Argh... Gosh... That hurt like hell...” He muttered in a raspy voice, shaking his head to remember where he was. Mephisto was impressed, eyes wondering to the back of the boy's head. His hair was sticky and covered in blood, but no wound was apparent. “Where am I this time?” He asked, blinking as his eyes began to adjust. Many were still filming and recording, watching in shock as the boy stood, wobbling at first like a drunkard before regaining his footing. One man walked up to the boy, glancing at him up and down unable to believe that the boy was alive and well. 

 

“A-Are you okay?!” He stuttered, placing his hands on the boy's shoulders. The boy blinked for a moment, before sending the worried man a smile. “Yeah I'm fine, happens all the time.” His answer intrigued Mephisto, as he watched the teen move back and grab his right arm. In seconds he twisted it back around from its broken state and popped it right into his shoulder socket without hesitating. “There we go,” he uttered to himself, moving his arm for a moment, before turning to send the man a quick nod. “Sorry for the scare, you can blame that boss of mine who was being a pain in the neck. I've got to go before the police arrive, I won't go through all of  _that_ again. Too much paperwork.” With that, the boy was gone, running off perfectly fine as though he didn't fall of a bridge.   

 

He ran from the crime scene, stopping shortly only to continue walking instead. He ignored passerby that stared, wondering about the blood on his clothes, and kept on his way. Studding his hands into his pocket, he glanced around as the minutes ticked by. He hadn't expect a crowd, it's been a while since he was surrounded like that.  

 

“How is it that when someone tries to kill themselves by jumping off a bridge into oncoming traffic, they end up alive and well?” 

 

Turning, the young teen couldn't help but frown at the demon sitting there, smiling at him. “Get out of here demon.” He growled, walking faster down the sidewalk. The last thing he needed was a demon, of all things, there. Today was not his day, first his boss scolds him, then he falls down the bridge, frightening civilians. It might get him into even more trouble now, he didn't need a demon taunting him. 

 

Just  _wonderful._  

 

“Allow me to introduce myself,” he began, making his way towards the boy and stopping before him, smirk in place as the teen almost bumped into him. “I am Johann Faust the fifth, headmaster of True Cross Academy. But, you may call me Mephisto Pheles, a pleasure to meet you.” The teen's eyes widened in shock, checking the headmaster from head to toe as though unable to believe that he truly was the headmaster of the prestigious academy. Scoffing, he sent him a glare and walked off, not believing the demon's lies.

 

“How rude!” Mephisto muttered, his smile not once fading as he turned to watch the boy walk away from him.

 

He was interested in him, interested in his ability and what he was capable of. Walking alongside him, Mephisto whistled and spun his umbrella, not caring that the male beside him was growing irritated by his very presence. He tried ignoring the demon, but once Mephisto opened his mouth and rambled on and on about True Cross Academy and his job, he snapped. 

 

Turning to Mephisto, he growled and reached for his belt, patting it down as though to look for something before sighing once realizing he didn't have his weapon. “Leave me alone demon! What do you want from me?!” He growled, hating the look on the headmaster's face. He seemed pleased, smiling victoriously at the teen. “A name would be nice, then I can get back to my car and back to the Academy.” He responded, trying not to laugh at the confused and angry teen.  

 

Grumbling under his breath, he sent Mephisto a sharp glare. Minutes passed them by, as the taller of the two waited patiently for an answer, not bothered by the many sending the two weirded out glances. The teen growled, before turning so that his back faced the headmaster. Glancing over his shoulder, the teen glared before responding. “(Y/n) (l/n).” Turning his head, he stormed off, hands tightened into fists. “Now leave me the hell alone!” 

 

Mephisto let out an amused chuckle, his pink limo driving up to him before stopping at his side. Opening the door to enter, he thought back to the boy that had gotten his attention and peaked his interest. 

 

“(Y/n) (l/n) hmm? I can't  _wait_  until we meet again.”


	2. Complicated

If there was one thing he was incapable of doing compared to his coworkers, it was controlling his temper when necessary. He's always the one to suddenly snap, anyone within 15 meters of him had to deal with whatever he has to dish out. It made life much more complicated than it already was for him, but it's even worse now that Mephisto Pheles entered without so much as an apology or being invited in. 

 

The headmaster barged right in, sort of like kicking the door down to one's home, and having to watch, being unable to do anything as he messed with your things, ate all your food and disorganized everything all while sending you a smug look from over his shoulder.

 

“I absolutely refuse!” He growled, sending his boss a harsh glare.

 

He's never gotten along with the man. He was too harsh, a bully despite being an exorcist, that and he showed [y/n] no respect at all. Now, [y/n] wasn't the type to ask for respect like a prick, but if you wanted to receive it, you needed to give it, and his jerk of a boss never gave it. 

 

Currently [y/n] was in said boss' office, standing before the man's desk and using his will power to not murder him in cold blood for the decision that had been made, all without consulting [y/n] about it. Apparently, his boss had gotten a call from the higher ups, asking to transfer [y/n] to work under Mephisto Pheles, and since his boss was a kiss-ass, he agreed without consulting the person in question. Imagine [y/n]'s shock when hearing he needed to go to his boss' office, only to be told about the decision without considering [y/n]'s feelings. 

 

“Well, you have no choice,” the man responded, going through his paperwork and not bothering to glance at him. “It's already been decided, and the higher ups are-”

 

“To hell with the higher ups!” [Y/n] screamed, baring his teeth. This shocked his boss, his head shooting up faster then when someone mentions his ex-wife's affairs. “ _I_ didn't say I'd go! And I've been with the Vatican helping their butts out when they needed it most, if I say I don't want to go, they'll take my word over yours!”

 

“As I've said, Mr. (L/n), you have no choice-”

 

[Y/n] just let out a yell, unable to hold himself back. He went on a rampage before his boss, tossing chairs, kicking things over and flipping his boss' desk over without much trouble. 

 

His boss was cowering, sweating buckets and watching in horror as his normally calm, kind, prude but obedient underling threw the biggest tantrum he's ever seen. There was a line set that made sure no one crossed it, but the boss hopped over it without hesitation. Once [y/n]'s raging fit was over, he huffed and turned to face the cowering man. His boss quivered, eyes widening when [y/n] inched closer and closer to him. “Fine, I'll go. But I shan't forget this and will be sure to tell them what you've done.” [Y/n] growled. “He's been asking for me to transfer for years and I've always,  _ALWAYS_ refused, but now you messed that up!”

 

With that, he turned around and pulled the office door open, making it his the wall with a loud SLAM! Causing it to open again with a now broken doorknob. It swayed and stayed open, all of his coworkers now able to see the mess inside. [Y/n] just stormed off, not bother to glance back knowing he had broken his boss' office door.

 

If he wanted a closed door, he had to do it himself.

 

-.-.-.-.-.-.-.-.-

 

Mephisto had been making his life complicated for years, just to get [y/n] to work for him. He's been at it since they met on the bridge, and now that he finally had him, he made sure [y/n]'s life was made difficult. 

 

He gave [y/n] much more work than the teen's ever had when he started as an Exwire, he doesn't even give any of his other employees that much work. He'd also make sure [y/n] worked in the same room as him, even had a desk specifically made for him next to his own desk. 

 

Mephisto had once made him train a rebellious bunch of trainees, because the previous trainer had gotten sick of dealing with them. They never listened, ignored orders nor respected their teachers. [Y/n] isn't one to disrespect, but when they began to curse or show him disrespect, he lost it. One student poked fun at his height, complaining about a 14/15 year old being an exorcist and not wanting to accept him as a teacher. 

 

Snapping, [y/n] smacked him and grabbed the front of his shirt, dragging him to the cages that held the giant, demon frogs in. The trainee was scared out of his mind and struggled to break free, but [y/n] held on tightly to his shirt collar. He shoved the teen's head through the bars of the cage, and proceeded to scold him, telling him that he'd be eaten by a low rank demon, simply because he refused to train and learn how to defend himself against them. 

 

The others were stunned by his boldness, and just as the demon was about to attack, [y/n] pulled the teen away and punched the frog's nose, ordering him to back off before dragging the teen up the stairs and scolding the other students. Since that demonstration, the never rebelled or disrespected [y/n] again. 

 

After that the young exorcist also had to do almost all of the paperwork, being handed piles and piles of it day in and day out with almost no breaks at all. Mephisto had informed him that it was only a forth of what _he_ had to deal with, and that [y/n] was a big help. Yeah, he doubted it. Mephisto was most likely doing it to complicate [y/n]'s life even further. 

 

He was also the one that had to clean up after Amaimon and his messes, no matter what he was doing or where he was going.

 

Another thing Mephisto does to make [y/n]'s life complicated, was name [y/n] the leader to a new group of exorcist that went on missions to get rid of low level demons within the area. They never took him seriously due to his height or his appearance, so [y/n] would just ignore him and go on with his mission. That is, until they were attacked. 

 

Shocking the others with his quick reflexes, he was able to finish the mission within seconds, indifferent expression upon his face as though he's done it a million times over. Many of them slowly began to fear him, then respect him, apologizing for their rude and childish behaviour. According to them, they assumed that Mephisto was playing a joke on them, since [y/n] looked 14 or 16 in their eyes. They never expected someone so young to be an experienced Dragoon. 

 

Although he was used to people underestimating him, it _did_ annoy him a little when they looked down on him.

 

[Y/n] was still angry with all the work given to him, and had requested time and time again to be transferred, but he was always told that the papers either didn't make it or hadn't been looked at. It made him want to throw a car at someone, anyone who even dared to look at him wrong. When he asked for another transfer from an exorcist who was going to meet with the higher ups, they'd ask for his name and details. But once told they responded that a transfer was impossible. 

 

But when (y/n) asked why, they never gave him a reason.

 

Entering his home, [y/n] walked in and sighed in exhaustion. He lived on his own in a one bedroom apartment, with a kitchen and small living area, not all that big. It was big enough to be comfortable for one person, and he's grown to love it. It was his safe haven, allowing him to relax and forget about his work. [Y/n] was also close friends with the landlord, and his neighbours were all kind to him, never questioning his working hours or exhaustion. They've seen him living on his own and continued to be surprised as he grew older yet never aged. His childlike appearance made them all protective of him, even though he was 24 years of age. 

 

They would bring him meals since he never seemed to eat, no matter how much he argued that he did. Though he will admit he did rarely eat, so he didn't blame them. Sure he knew how to cook for himself, but with how busy he's gotten, working for trash known as Mephisto Pheles, he'd eat out or just inhale a cup of instant ramen noodles. 

 

Still, their kindness and concerns made him smile, it was rare that he had someone there to care for him, and he wouldn't trade that for the world.

 

After a shower, he changed into a plain white t-shirt and boxers, and headed towards his kitchen. Putting on the kettle, he pulled out his favourite cup ramen and prepared it, waiting a minute before grabbing a for and sitting down to watch some television. Finally, he could relaz without dealing with his so-called 'boss' and all of his useless shenanigans. 

 

But his peaceful night at home was ruined, once again, by that jerk of a demon.

 

Next to his couch was a large window, curtains drawn with it slightly open to let in a breeze, when a bird suddenly entered the room through the opening. It was a very pretty pink owl, a poka-dot scarf around his neck with large, tired eyes. Now, [y/n] hated demons, he didn't trust them for shit. But he was sucker for cute things and birds, he loved birds. “Hello little guy,” he greeted, smiling when the owl flew and stood on [y/n]'s right leg, claws gently hooking around him to keep itself in place. His eyes gazed up at the man with intrigue, as though trying to understand or read him. 

 

“What are you doing here?” He asked, lifting a hand and running it gently through the owl's soft feathers. “You're so pretty, where're you from?” The owl seemed surprised at first, before ruffling its feathers and moving closer to receive more affection. [Y/n] continued to run his fingers through the owl's feathers, smiling when the bird cooed and purred softly. Minutes passed by until he spotted the letter dangling from the owl's neck. 

 

Furrowing his eyebrows, he reached down and plucked it off of its collar slowly, making sure not to hurt the owl before opening it. [Y/n] growled when he noticed Mephisto's handwriting, no doubt another task for him to complete. It took everything he had not to throw his television across the room, he just needed to calm himself down. Opening the letter, he began to read, the rage growing inside of him as he read every word. 

 

“Is he serious?!” [Y/n] growled, causing the owl to flail and fly away from him in shock. The owl stood on top of [y/n]'s table and watched completely surprised, as the young Dragoon continued to throw things around. He resembled an angry child throwing a tantrum, what with his childlike appearance and all, but it did look rather frightening when you notice how serious he was. As it turns out, he had to pack his stuff up and leave, because Mephisto had reserved a room for him at a dorm, and paid off his the rest of his lease.

 

That meant he couldn't even live in his safe haven anymore, he had to live where the man could keep a closer eye one him. No, no!

 

He refused!

 

There was no way to make him, and even if there were what were they going to do? Kill him?

 

Hah!

 

Laughable!

 

Throwing the letter onto the ground, he stomped on it a couple of times, went to the kitchen and came back to pour some oil on it, before lighting it on fire with his lighter. He didn't care how unsafe it was, and if his apartment caught on fire, it would be Mephisto's fault.

 

Look at him, a grown man acting like a spoiled brat, how pathetic.

 

The owl tilted its head, eyes glowing with amusement and intrigue, as [y/n] turned on his heels and entered his bedroom. He didn't emerge until the fire grew in size. He didn't bother much with it, just throwing a water bottle at it and watching as it sizzled before he turned to the owl. Without a word, he clipped a letter to the owl's scarf with a safety pin, petting it gently and pointing to the open window. “Give that to Mephisto, and tell him to suck a fat one.” With that being said, he put on his shoes, slid on a coat and grabbed his keys and wallet, before leaving.  

 

If he was going to move out, he'd make sure there was a reason for  _him_ to leave, and not because the purple haired headmaster told him to.

 

Sure he was setting his house on fire, bit it was a better excuse than saying  the headmaster ordered him to. His pride wouldn't let him be told what to do, he'd rather do something petty like this, burning half of his belongings along with some important documents, then acknowledge the fact that he might be doing exactly Mephisto wanted.

 

“I shan't let you get your way today you jerk.” He grumbled under his breath as he walked away from his apartment building, heading towards a nearby bar.

 

“Not today.”

 

-.-.-.-.-.-.-.-.-

 

He placed the only box of his belongings onto the ground, heaving a sigh when he examined the empty bedroom. Arriving at the large, empty dorm earlier than expected, and ignoring Mephisto's request to wait for him to pick him up, he made the room his own with what little items he had that had survived the fire.

 

Just as planned, his apartment went up in flames, fortunately it was only his apartment and none of the others were hurt. When Mephisto had gone to meet him, he looked beyond amused by the shorter male, smile in place and eyes gleaming with a knowing sparkle. He knew what [y/n] had done, and he was impressed by how bold and stubborn he was. Before [y/n] could blame Mephisto for everything, the purple haired demon handed him another envelope. He didn't say much after that, he just walked away, a small skip in his step, entered his pink limo and drove off. 

 

In the envelope were instructions for a new mission he had, one that he knew the headmaster had planned all along. 

 

He had to watch over and take care of the two sons of Satan. 

 

He hated babysitting for personal reasons, sure he liked kids, but he didn't want to take care of a pair of grown demons who seem to cause more trouble than they're worth. He fussed and complained about it to Mephisto, ignoring the man's compliments on how skillful he was and nearly attacked him if it weren't for the other exorcists in the room that held him back. All were amazed that [y/n] didn't care if he got in trouble, and envied him for it, but stopped him whenever he saw the opportunity to attack Mephisto. Mephisto in return, just smiled and laughed, commenting again and again on how fond of the [h/n] haired male he was becoming. 

 

“Fond? Yeah right,” (y/n) grumbled, making his bed with clean sheets before going to the desk and setting it up. “You just seem to find annoying me amusing.” 

 

If [y/n] had any say in it, he'd rip the man apart in seconds. What were they going to do with him? Execute him? He'd love to see them try it, and he'd love it even more they actually succeeded. [Y/n] didn't have much to decorate his desk with, since most of his belongings were trashed in the fire, but that didn't matter. Material objects meant nothing to him. With a deep sigh, he glanced around the room and couldn't help but feel as though he were being watched. 

 

No doubt it was Mephisto's doing, it was obvious to him that Mephisto had bugged the place with cameras and audio, but he knew that the man wasn't really up for getting attacked by the shorter male. That, and it made the most sense to him to be observed, since he had a power that seemed to intrigue the purple haired demon. 

 

Exiting his bedroom, he made his way down the hall and towards the kitchen. He hadn't had the chance to eat since he had woken up that morning for work, it was already late evening. As he entered the dining hall, he couldn't help the gasp that escaped his lips when he saw it. 

 

The black demon tail with the fluffy, furry end poking out the entryway to the kitchen. 

 

Pulling out his gun, the young Dragoon slowly made his way towards the tail, tip toeing softly as to not get caught. He's seen that same tail not only on Mephisto, but the green haired bastard of his brother. He's been around the headmaster enough to recognize the tail, and this was different from the one that belong to the purple haired demon or his green haired annoyance called his brother. Mephisto's tail held a dark, purple hue to it when it shined in the light, and it was well groomed. His brother's held a green hue to his own tail, and his fur was rather spiked around the end, with split ends. 

 

This tail was rather messy, and held a blue hue to it. 

 

Making it to the entrance, he pressed his back to the wall, making himself invisible. He hated himself for saying this, but he was glad that he was rather short and small enough to hide. He heard the clanging of the many plates and other kitchen utensils, and the soft sound of humming. 

 

The demon was male. 

 

(Y/n) couldn't help but purse his lips, his hands clenching his gun and eyes squeezing tight. He couldn't help but grit his teeth, trying to push down his guilt.   
  
The demon was but a boy, a child in his eyes.   
  
But he was a demon, and a demon was evil regardless of age. Demons were prone to using the presence of a child, or feigning innocence in order to get to a human. They would mimic a child's laughter, their voice and even their appearance. Taking in a deep breath, he quickly lifted his hand and turned in time to point the gun at the demon.    
  
“Gah!”  
  
There stood a young teen, white apron on while holding a bowl with a batter of some sort. His electric blue eyes were staring right at him, wide in both shock and confusion. He stared at the Dragoon, then at the gun, then back at the Dragoon, before he finally understood the situation. “Wait wait!” He began, slowly placing the bowl down onto the table, before lifting his hands up as though to show his surrender. “Don't shoot! Mepisto told me that you'd be here! Don't shoot!”   
  
“Of course that bastard would force me to come here and not tell me a demon child was also here.” The Dragoon muttered, before heaving a sigh. There was no point in harming the child now, especially since he didn't sense any hostility from him whatsoever. Placing his pistol back into its holder, he made sure to examine the child.   
  
Spiky black hair, messy and unkept. Bright, electric blue eyes, and a relieved expression on his face. His tail swayed a bit, looking rather comfortable as he looked down at the batter he was stirring. “Sorry about that kid,'' the Dragoon apologized, sending the boy an apologetic smile. “'Just being cautious.”  
  
“It's alright,'' the boy responded, sending him a smile in return. “You were just- Wait, kid? You're younger than me! You're the kid!”   
  
(Y/n) would have gotten mad at him for calling him a kid, but he just couldn't bring himself to get angry. Curse him and his unnatural love for those he considers children. “I'm older than _you_ , so _you're_ the kid.”   
  
Right as the boy was about to speak again, the sound of footsteps reached both their ears. (Y/n) immediately went on high alert, placing his hand on his gun should he have to shoot at any and all intruders. He was told that he'd be there taking care of two kids, but if one was in the kitchen, the other was either in his room or out with friends. He hadn't actually met the two boys, nor had he read their file, but he'll probably recognize them when he saw them.   
  
“Nii san?”  
  
“Ah,” the boy in the kitchen muttered, turning to walk around the small counter and towards the doorframe. “Hey, we're over here.” He called out, but he hadn't been able to walk out, for (y/n) turned around and pulled out his gun, right as the person did so as well.   
  
There they stood face to face, guns pointed at one another. (Y/n) glared the man down, finger on the trigger and ready to shoot. He wasn't afraid to take a life, he had done so a million times over in his life time, and he'll do it again if it means he gets to protect not only himself, but the boy he was sent there to keep an eye on. It wasn't until his opponent started to lower his gun that he realized who he was facing off against, and in all honesty, he was surprised.   
  
“(L/n) sensei?”


End file.
